Lagasse was born on October 15, 1959, in Fall River, Massachusetts to a French-Canadian Québécois father, John Lagassé, and Portuguese mother, Hilda. Lagasse worked in a Portuguese bakery as a teenager where he discovered his talent for cooking and subsequently enrolled in a culinary arts program at Diman Regional Vocational Technical High School.[1] His talents as a percussionist earned him a scholarship to the New England Conservatory of Music but he chose instead to attend Johnson & Wales University in hopes of becoming a chef. He met his first wife, Elizabeth Kief, while working at a restaurant called "Venus De Milo" to pay his way through school.[1] He attended Johnson and Wales in 1978 and the school later awarded him an honorary doctorate.[5]

After the birth of daughters Jessica and Jillian,[7] Elizabeth Kief and Lagasse divorced. Lagasse married a second time to a fashion designer, Tari Hohn, but that too ended in divorce.[6] Lagasse was married a third time on May 13, 2000 to a real estate broker, Alden Lovelace.[6] He and Lovelace had a son, Emeril John Lagasse IV, on March 2003, and a daughter, Meril Lovelace Lagasse, on December 10, 2004.[7]

Lagasse graduated from the culinary school Johnson and Wales in 1978 and became Executive Chef at the Dunfey's Hyannis Resort in 1979. He was nominated as Chef of the Year in 1983.

Lagasse gained fame in the culinary world as executive chef of Commander's Palace in New Orleans. After leading the kitchen there for seven and a half years, he opened his first restaurant, Emeril's, in New Orleans, Louisiana, in 1990. It was designated "Restaurant of the Year" in Esquire magazine that year. Lagasse is known for his emphasis on Creole and Cajun cooking styles. Many of his restaurants, as well as his corporate office, Emeril's Homebase, are located in New Orleans. Today, Lagasse is the executive chef and proprietor of thirteen restaurants in New Orleans, Las Vegas, Orlando, Charlotte, and Bethlehem, Pennsylvania.

Lagasse first appeared on television on the show Great Chefs where he was featured on no fewer than ten episodes, including Great Chefs, the Louisiana New Garde, New Orleans Jazz Brunch and Great Chefs — Great Cities. [8] After several appearances on several other FoodTV programs, Lagasse hosted his own show, The Essence of Emeril. “Essence” in the title refers to Emeril’s Essence, the name of a spice blend of his own concoction that he frequently uses in his cooking, and which is commercially available in several flavors. He also often suggested that viewers of his show create their own spice blends that reflect their personal tastes and be unafraid to use them to customize the dishes he would teach. In early 1997, “Emeril Live” began production. Later that year, “Emeril Live” won a Cable Ace Award for “Best Informational Show” of 1997. By 1998, Emeril became a food correspondent for ABC’s “Good Morning America,” which he continues today. [9]

Lagasse was one of sixteen chefs featured in the 1993 Julia Child series, "Cooking With Master Chefs."

On television, Lagasse is known for his light and jovial hosting style as well as several catchphrases, including "Bam!" Emeril's signature catchphrase began simply as a means of keeping his studio crew awake. When Emeril first began at Food Network, he would tape seven shows a day, from seven in the morning until two in the afternoon. He would frequently pepper his dialogue with "BAMS!" to keep his crew in the studio awake, focused, and on their toes. The phrase soon proved a hit with viewers... and a catchphrase was born.[10] "Kick it up a notch," "Aw, yeah, babe" and "Feel the love," are usually said before or after adding something spicy to a dish, or after the reaction to adding something. When frying or making dishes like sausage, Lagasse advocated using genuine lard, boasting, "Pork fat rules!" This style developed fully and Lagasse became more comfortable when a live studio audience was added in the change from Essence of Emeril to Emeril Live.

Lagasse acted as Grand Marshal of the 2008 Tournament of Roses Parade and presided over the nationally telecast coin-toss before the game wearing a business suit—a rarity for Lagasse who is normally attired in chef's garb.

In 2009, Lagasse joined Bravo's Top Chef as a judge. He also was a guest judge during season 9 of Top Chef: Texas in 2011 and joined the judges' table for seasons 10 and 11 in Seattle and New Orleans, respectively. During season 11 of “Top Chef: New Orleans,” Emeril’s Restaurant was the featured location and the episode’s winning dish was featured on the menu at the restaurant.

In September 2011, he hosted a show from Hallmark Channel called Emeril's Table. It was cancelled after one season.

On the animated television show Futurama, Lagasse is parodied by the alien Chef Elzar, who often uses Lagasse's signature "BAM!" and "Knock it up a notch!"

In 2012, Lagasse appeared as himself on an episode of the HBO drama series Treme.

In 2013, Lagasse began hosting a new Cooking Channel show, Emeril's Florida. This began airing its second season in early 2014. In March 2014, TNT announced the production of a new cooking reality show, On the Menu, featuring Lagasse as Menu Master along with host Ty Pennington. [14]

In August 2006 Lagasse contributed several recipes to the meal selection aboard the International Space Station, as part of a general NASA effort to improve the quality of the food supply for astronauts. Lagasse’s cuisine in particular was selected in the hopes that the spicier fare would offset the reported tendency of microgravity to deaden flavors.[15]

Established in 2002, Emeril Lagasse Foundation supports non-profit organizations and educational initiatives that create new opportunities for children, especially for those from disadvantaged circumstances, to realize their full potential as productive and creative individuals, and to make a lasting impact on their lives.

Emeril Lagasse Foundation has distributed more than $6 million in grants for children’s charities. Projects funded by the Foundation include an outdoor classroom, gardens, fresh foods cafeteria and teaching kitchen at Edible Schoolyard New Orleans, an accessible learning kitchen for special needs students at St. Michael Special School, a four-year culinary arts program for high school students at New Orleans Center for the Creative Arts, the Emeril Lagasse Foundation Hospitality Center at Café Reconcile, and hospitality training at Liberty’s Kitchen for at-risk youth preparing healthy school meals. Each fall, the foundation hosts its signature annual fundraiser, Carnivale du Vin, which ranks among the “Top Ten U.S. Charity Wine Auctions” in Wine Spectator magazine. The Foundation introduced charity indoor/outdoor food and music fest, Boudin, Bourbon & Beer in 2011. In 2013, Lagasse was honored as James Beard Foundation Humanitarian of the Year.

Lagasse’s unique style of cooking is called "New New Orleans:" a unique style of using local, Louisiana ingredients in his own interpretation of Creole cuisine, strongly influenced by Asian, Portuguese, Southwestern, and other cultures which themselves influence New Orleans cuisine. [16] However, the styles of cuisine at Lagasse’s restaurants are not all the same. Emeril’s Tchoup Chop in Orlando serves kicked-up Asian and Polynesian cuisine, while Delmonico Steakhouse at The Venetian in Las Vegas is a classic steakhouse with a Creole flair, and Emeril’s Italian Table serves rustic Italian-inspired fare.

Lagasse has a wide range of branded products. On June 8, 2000, he signed a deal with B&G Foods to create a line of dry grocery products marketed under the label "Emeril's."[17] The product line includes pasta sauces, marinades, salsas, and Lagasses' signature "Essence" spice blend. In 2004 he lent his name to a line of fresh produce made by Pride of San Juan. These products, branded "Emeril's Gourmet Produce," include spring mix salad blends, fresh herbs, and heirloom tomatoes. Lagasse's complete assortment of products can be found on his own store web site at http://www.emerilstore.com/ .

Lagasse also has two lines of kitchen knives produced by Wüsthof and cookware made by All-Clad, as well as a line of kitchen electrical appliances made by T-Fal.

On February 19, 2008, Martha Stewart Living Omnimedia announced it had acquired the rights to all Emeril products including cookware, cookbooks, television shows, and food products in a $50 million agreement. Lagasse retains rights to his restaurants and corporate offices.[18]